Probiotics: More Evidence of Efficacy

Action Points

This is a systematic review and meta-analysis of randomized, controlled trials designed to assess the efﬁcacy and safety of probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children receiving antibiotics.

The study found that there was moderate-quality evidence suggesting that probiotics are both safe and effective for preventing Clostridium difﬁcile-associated diarrhea (CDAD).

Probiotic supplements are a cheap, safe, and effective way to prevent Clostridium difficile-associated diarrhea, according to a systematic review by the Cochrane Collaboration.

In a case-analysis of 23 trials involving 4,213 people, prophylactic probiotics reduced the risk of C. difficile diarrhea by 64%, compared with people given no treatment or placebo, reported Bradley Johnston, MD, of The Hospital for Sick Children Research Institute in Toronto, and colleagues.

Specifically, the incidence of C. difficile diarrhea was 2.0% in the probiotic group compared with 5.5% in the placebo or no treatment control group (RR 0.36; 95% CI 0.26-0.51).

The findings add to a growing body of evidence that prophylaxis with probiotics confers protection against diarrhea in people taking antibiotics. That protection comes via a variety of mechanisms -- improving the microbial balance of the host, counteracting disturbances in intestinal ﬂora, and reducing the risk of colonization by pathogenic bacteria, the researchers wrote.

Johnston noted that probiotics are becoming increasingly available as capsules and dairy-based food supplements in health food stores and supermarkets.

The cost is generally low, about $15 to $40 for a month supply online. In contrast, the estimated cost of treating primary C. difﬁcile infections ranges from $2,871 to $4,846 per case in the U.S. Recurrent cases run $13,655 to $18,067.

The incidence of C. difﬁcile infection, a secondary outcome, was 12.6% in the probiotics group compared with 12.7% in the placebo or no treatment control group (RR 0.89; 95% CI 0.6-1.24).

"This suggests that probiotics act to prevent the symptoms of C. difficile infection rather than to prevent the infection itself," said Johnston.

Further study is needed to determine why taking probiotics in combination with antibiotics helped to prevent C. difficile diarrhea, but did not reduce C. difﬁcile infections, Johnston said.

Patients asking for advice should be told to look for a brand they trust and whose label offers detailed information on what bacteria they contain, Mark H. Mellow, MD, director of the Inteiris Digestive Health Center in Oklahoma City, told a recent seminar.

Use of probiotics is popular among patients -- and regularly advocated in TV and print ads. Do you recommend probiotics to your patients embarking on a course of antibiotics? Let us know by Adding Your Knowledge below. -- Sanjay Gupta, MD

The authors had no disclosures.

Mellow had no disclosures.

Reviewed by Zalman S. Agus, MD Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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